Publication detail

Multiaxial stress-strain response and displacive transformations in NiTi alloy from first principles

ŠESTÁK, P. ČERNÝ, M. HE, J. ZHANG, Z. POKLUDA, J.

Original Title

Multiaxial stress-strain response and displacive transformations in NiTi alloy from first principles

Type

journal article in Web of Science

Language

English

Original Abstract

Present ab initio study was focussed on a response of NiTi martensite to a superposition of shear and tensile or compressive stresses acting normally to the shear planes. The theoretically predicted basecentered orthorhombic (BCO) ground-state structure was found unstable under uniaxial compression and two transformations, one from orthorhombic to a monoclinic symmetry and the other back from monoclinic to orthorhombic symmetry, were observed in the computational model. The former transformation shows that the uniaxial compressive stress of about 4 GPa destabilizes the BCO structure by reducing its symmetry to the experimentally observed monoclinic one. However, superposition of small shear stresses remarkably lowers the compressive stress necessary for this destabilization. The latter transformation then draws the crystal lattice to the B19 structure. The theoretical shear strength of NiTi martensite was subsequently computed as a function of the normal stress. The results obtained show that the effect of the normal stress is surprisingly opposite to that calculated for NiTi austenite and other cubic metals, i.e., that the shear strength is lowered by the compressive normal stress and vice versa.

Keywords

NiTi martensite; Displacive transformations; Ab initio calculations; Strength and stability; Multiaxial loading

Authors

ŠESTÁK, P.; ČERNÝ, M.; HE, J.; ZHANG, Z.; POKLUDA, J.

Released

1. 5. 2016

ISBN

1359-6454

Periodical

Acta materialia

Year of study

109

Number

5

State

United States of America

Pages from

223

Pages to

229

Pages count

7

URL

http://dx.doi.org/10.1016/j.actamat.2016.02.043

BibTex

@article{BUT122518,
  author="Petr {Šesták} and Miroslav {Černý} and Jianying {He} and Zhiliang {Zhang} and Jaroslav {Pokluda}",
  title="Multiaxial stress-strain response and displacive transformations in NiTi alloy from first principles",
  journal="Acta materialia",
  year="2016",
  volume="109",
  number="5",
  pages="223--229",
  doi="10.1016/j.actamat.2016.02.043",
  issn="1359-6454",
  url="http://dx.doi.org/10.1016/j.actamat.2016.02.043"
}